AFFECTING FACTORS ON AIR VOID SYSTEM AND FROST RESISTANCE OF CONCRETE

The influence of various factors such as chemical admixture and mixing conditions on the air void system of concrete was investigated by the buoyancy method. When AE agent was used independently, the difference of quantity and quality of entrained air due to the type of AE agent was not recognized among 10 types of AE agent used in this study. However, when AE agent was used with superplasticizer, we could see big difference in air entraining due to the type of AE agent. Furthermore, the influence of mixing efficiency and grading of sand was also large besides AE agent. It was possible to control frost resistance by the appropriate quantity and quality of entrained air even if concrete was subjected to wetting/drying cycles. The section air quantity of diameter from 100 to 500 micrometer is especially effective to prevent frost damage of concrete